Then will I teach transgressors thy ways; and sinners shall be converted unto thee.
-He promises spiritual sacrifices of praise, and efforts for the conversion of other transgressors, as the fruit of his being restored to the joy of salvation. For though works do not justify, the justified man is sure to work. God works in the evidences of faith. So in Psalms 54:6-7, but especially in the parallel psalm, he passes from his own blessedness in experienced pardon to 'teaching others God's way' of peace,-namely, God pardoning all who heartily confess their sins (Psalms 32:8-9). As here, in Psalms 51:1-19, he promises to do so, so in Psalms 32:1-11 he fulfills his promise. This portion falls into three divisions:
(1) He states positively how he will evince his gratitude to God (Psalms 51:13-15).
(2) He renounces false thanksgivings, as opposed to the true ones which he offers-namely, a contrite heart (Psalms 51:16-17).
(3) He passes from individual thanksgivings to those of Zion, or the whole Church.
Verse 13. Then will I teach transgressors thy ways; and sinners shall be converted unto thee. - when my prayer shall have been heard. Even already, in some degree, his prayer was heard. For the wish to bring sinners to God evinces a state of heart no longer estranged from God's salvation, and from concern for His honour. "Thy ways" are ways whereby sinners are to go-the ways of conversion, as the parallel clause proves.
Verse 14. Deliver me from blood-guiltiness - literally, bloods, plural; namely, the guilt of having shed Uriah's blood, and that of others with him (2 Samuel 11:15-17; 2 Samuel 12:9-10). This denunciation rested as a heavy and the completion of "the wall round about" was effected by Solomon (1 Kings 3:1; 1 Kings 9:15). There is doubtless also a figurative sense proved by the parallel "do good," and by the analogy of what David sought for himself-namely, salvation. Thus build the walls is equivalent to establish in temporal and spiritual prosperity Zion, thy people. Compare the phrase, Isaiah 60:10; Zechariah 6:15; Revelation 20:10-12; also Psalms 89:40. These two verses have been made the pretext for transferring this psalm to a date after the captivity, when the walls of Jerusalem were prostrate. But the Psalmist does not say 'build them again,' but 'build them.'
Verse 19. Then shalt thou be pleased with the sacrifices of righteousness - sacrifices offered in righteousness (Psalms 4:5); not such as are vain (Isaiah 1:13), the offerers being tainted with unpardoned sin (Leviticus 26:31). As in Psalms 51:16, heartless sacrifices are rejected, so here in Psalms 51:19, hearty sacrifices are promised as acceptable to Yahweh.
With burnt offering, and whole burnt offering - (Deuteronomy 33:10.) The "whole burnt offering," more emphatically than the "burnt offering," marks why this offering in particular is promised-namely, because the whole was burnt, the offerer retaining no part (1 Samuel 7:9); thus, there is implied entire self-surrender to God, the soul burning with love, and spending itself wholly to His glory.
Then shall they offer bullocks upon thine altar - literally, 'then shall bullocks ascend thine altar.'